1. Field
A positive active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same are disclosed.
2. Description of the Related Art
A rechargeable lithium battery has recently drawn attention as a power source for small portable electronic devices. It uses an organic electrolyte solution and thereby, has twice or more as high discharge voltage as a related art battery using an alkali aqueous solution and accordingly, has a high energy density.
This rechargeable lithium battery is used by injecting an electrolyte into an electrode assembly including a positive electrode including a positive active material that can intercalate and deintercalate lithium, and a negative electrode including a negative active material that can intercalate and deintercalate lithium.
For the positive active material, a composite metal oxide such as LiCoO2, LiMn2O4, LiNiO2, LiNi1−xCoxO2 (0<x<1), LiMnO2, and the like has been used. LiNiO2 among the positive active materials has high charge capacity but is difficult to synthesize, while an Mn-based active material such as LiMn2O4, LiMnO2, and the like is easy to synthesis, relatively inexpensive, and less of an environmental contaminate, but LiMnO2 has small capacity. In contrast, LiCoO2 shows electrical conductivity of about 10−2 S/cm to 1 S/cm at room temperature, high battery voltage, and excellent electrode characteristics and thus, has been widely used; but LiCoO2 has low stability during high-rate charge and discharge.
Accordingly, developments for a substitute material because of electrochemical performance and stability due to the positive active material have been actively made.